Institut für Anorganische Chemie, Institut für nachhaltige Chemie & Katalyse mit Bor (ICB), Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.
Merck KGaA, 64293, Darmstadt, Germany.
Angew Chem Int Ed Engl. 2017 Mar 1;56(10):2795-2799. doi: 10.1002/anie.201611899. Epub 2017 Jan 24.
The first deprotonation of a borohydride anion was achieved by treatment of [BH(CN) ] with strong non-nucleophilic bases, which resulted in the formation of alkali-metal salts of the tricyanoborate dianion B(CN) in up to 97 % yield and 99.5 % purity. [BH(CN) ] is less acidic than (Me Si) NH but a stronger acid than iPr NH. Less sterically hindered, more nucleophilic bases such as PhLi and MeLi mostly attack a CN group under formation of imine dianions [RC(N)B(CN) ] , which can be hydrolyzed to ketones of the [RC(O)B(CN) ] type. The boron-centered nucleophile B(CN) reacts with CO and CN reagents to give salts of the [B(CN) CO ] dianion and the tetracyanoborate anion [B(CN) ] , respectively, in excellent yields.
硼氢阴离子的首次去质子化是通过用强非亲核碱处理[BH(CN)]来实现的，这导致了三氰基硼酸二阴离子 B(CN)的碱金属盐以高达 97%的产率和 99.5%的纯度形成。[BH(CN)]的酸性比(Me Si)NH 弱，但比 iPr NH 强。空间位阻较小、亲核性更强的碱，如 PhLi 和 MeLi，在形成亚胺二阴离子[RC(N)B(CN)]时主要攻击 CN 基团，后者可以水解成[RC(O)B(CN)]型的酮。硼中心亲核试剂 B(CN)与 CO 和 CN 试剂反应，分别以优异的收率得到[B(CN)CO]二阴离子和四氰基硼酸阴离子[B(CN)]的盐。
